I think in discussing the info you have to date on these decoys, you may have answered your own question.
The heads, without a view of the bodies, really looked like East Coast heads to me. When you showed the bodies, then I got a bit confused, as some had east coast lines, others do not.
I often found, when searching for decoys in Illinois, 6 or more unpainted, well done, decoy heads, made by the same unknown maker, sitting with a bunch of crude decoys. One older guy told me that his dad had ordered heads from makers/carvers/suppliers to have on hand to replace heads that broke off. Having heard that, I watched as I picked over repainted and beat up decoys and saw matches of those unpainted heads on non-descript bodies by other makers. I had no use for them at the time, and sold most of the old, unpainted heads I found to Dave Frier, who used them to "fix" old woooden decoys that he stripped, repainted, and stained to sell in his antique shop and at decoy shows. Maybe one or more of your heads are of this type of origin, but most seem to be made for the decoys they are found on, matching the bodies pretty well.
Relatedly, decoy collectors have proven an east coast connection for decoys found in several midwestern gunning locations, especially premier ones that had monied members and/or members who traveled from the Easst Coast to hunt. Those decoys did influence local makers, and you can end up with local decoys that blend east coast and local styles....
But this is the great part of collecting decoys to me, all the unknown and untold stories, even after all these years.....